Deinking paper stock



Patented is, 1926.

UNITED STATES PATIENT OFFICE.

MOORE PAPER (30., OF PHILADELPHIA,

MASSACHUSETTS.

PENNSYLVANIA, A CORPORATION or DEINKING PAPER s'rocx.

No Drawing.

T all whom it HZUfI/COHCGTR.

Be it known that I, JosErH E. PLUM'srn-m,

a citizen of the United States, and resident of W'ihnington. in the county of New Castle and State of Delaware, have invented certain new and useful Improvements in Deinking Paper Stock, of-which the following is a specification.

My present invention relates to a process 19 of de-inking printed stock or de-colorizing colored stock and bleaching the same in order to produce commercial pulp and paper therefrom.

The principal object of the invention re? sides in simultaneously deterging and bleaching the printed or colored stock in one and the same batch.

To this end the invention contemplates the mixing of the macerated mass of printed stock with a reagent which contains a mixture of alkali and its hypochlorite. ordinarily in the presence of elevated temperature. The usual method for de-inking-paper stock at present in vogue among commercial plants, is to macerate the stock in water 1 until the consistency is such that thestock will flow.

This maccrated stock is agitated with 3 usually carbon. After this operation has been carried on for a )roper length of time, the stock is washer rce of the alkali and ink and then a calcium h-ypochlorite bleach u'ed. The use of commercial calcium hypm chlorite bleach is undesirable because of the fact that" there is a considerable amount of carbon dioxide pre:ent in the batch which results in the formation of insoluble calcium carbonate which cannot be completely re moved which tends towards producing an inferior product. After the bleaching "period a second washing must take place; 4

fibers, thoroughly saponify the vehicle and at the, same time to whiten any organic,

coloring matter which. may be present,

an alkali in order to saponify the ink vehicle and free the ink or color pigment which ismaking the normal number of steps four Application filed November 16, 1925. Serial ITO. 65,499.

have found that the proportion of the alkali which must be present as hypochlorite will vary from to 75% of the total soda-used and that the total soda ufed will vary from 5 pounds to 20 pounds per 100 pounds of paper stock used. These variations are caused by the difference in the desired quality of ultimate product and also by the differences in the quality of stock to be treated. I have also foundthat it is necessary to agitate the heated mixture for periods varying from minutes to 6 hours depending upon the kind of stock used and the quality desired in the finished product.

By the use of soda ash,'or caustic soda,

and liquid chlorine in the reaction mixture,

I find that I am able to simultaneously dcterge and beach in the one operation, and get at the same time a superior color in addition to cutting down the time of operationl and the quantityv and cost of materials use I have found that either soda aih or caustic soda may be used, as the alkali in the process, the choice of the two depending upon which is commercially available, as

each gives excellent results.

Having thus described my invention, what I claim is: 4

l. A method of de-inking paper stock. which con'ists in treating the same with an alkali and a corresponding. hypochloi-ite. 2. A method of tie-inking paper stock.

which consists in maccrating the stock and I then treating the same with a soluble alkali and a soluble hypochlorite.

3. A method of tie-inking paper stock.

which consists in macerating the stock and then treating the same simultaneously with an alkali and sodium hypochlorite.

4. A method of (lo-inking paper stock, which comists in macerating the same. agitatingthe mace'rated' stock with an alkali. introducing chlorine to said mixture, and cooking the resultant mixture.

5. A method of de-inking paper stock, which consists in macerat'ing the same with an alkaline sodium compound, introducing liquid chlorine to the agitated mass until from 25 to 75% of the soda has combined therewith to form sodium hypochlorite, and then cooking the mass. I

In testimony whereof, I afiix my signature.

JOSEPH E. PLUMSTEAD. 

